13,579 research outputs found
Elastic properties of carbon nanotubes and their heterojunctions
Comprehensive studies on the modelling and numerical simulation of the mechanical behaviour under tension, bending and torsion of single-walled carbon nanotubes and their heterojunctions are performed. It is proposed to deduce the mechanical properties of the carbon nanotubes heterojunctions from the knowledge of the mechanical properties of the single-walled carbon nanotubes, which are their constituent key unit
Scotin, a novel p53-inducible proapoptotic protein located in the ER and the nuclear membrane
p53 is a transcription factor that induces growth arrest or apoptosis in response to cellular stress. To identify new p53-inducible proapoptotic genes, we compared, by differential display, the expression of genes in spleen or thymus of normal and p53 nullizygote mice after γ-irradiation of whole animals. We report the identification and characterization of human and mouse Scotin homologues, a novel gene directly transactivated by p53. The Scotin protein is localized to the ER and the nuclear membrane. Scotin can induce apoptosis in a caspase-dependent manner. Inhibition of endogenous Scotin expression increases resistance to p53-dependent apoptosis induced by DNA damage, suggesting that Scotin plays a role in p53-dependent apoptosis. The discovery of Scotin brings to light a role of the ER in p53-dependent apoptosis
Detection of new eruptions in the Magellanic Clouds LBVs R 40 and R 110
We performed a spectroscopic and photometric analysis to study new eruptions
in two luminous blue variables (LBVs) in the Magellanic Clouds. We detected a
strong new eruption in the LBV R40 that reached in 2016, which is
around mag brighter than the minimum registered in 1985. During this new
eruption, the star changed from an A-type to a late F-type spectrum. Based on
photometric and spectroscopic empirical calibrations and synthetic spectral
modeling, we determine that R\,40 reached ~K
during this new eruption. This object is thereby probably one of the coolest
identified LBVs. We could also identify an enrichment of nitrogen and r- and
s-process elements. We detected a weak eruption in the LBV R 110 with a maximum
of mag in 2011, that is, around mag brighter than in the
quiescent phase. On the other hand, this new eruption is about mag
fainter than the first eruption detected in 1990, but the temperature did not
decrease below 8500 K. Spitzer spectra show indications of cool dust in the
circumstellar environment of both stars, but no hot or warm dust was present,
except by the probable presence of PAHs in R\,110. We also discuss a possible
post-red supergiant nature for both stars
Development of a low-cost smart parking solution for smart cities
The pressure of traffic on modern cities keeps growing. More and more vehicles flow into the city draining the existing parking resources and increasing traffic congestions and fueling the pollution increase. In this paper we present a solution for a low-cost smart parking system and all the software and hardware components that were developed and integrated in a smart parking prototype. The developed prototype is based on Arduino for the sensor network and on the Raspberry Pi for the gateway device. This paper also describes some of the technology aspects used in the communication between the sensors and the gateway – based on the ZigBee protocol. In addition to the hardware part of the prototype, the used backend architecture and the mobile application, that enables the user to find quickly and efficiently a parking spot, are also analyzed in this paper.info:eu-repo/semantics/publishedVersio
Controlo visual de um tapete-rolante
No presente artigo é apresentado o trabalho realizado no Laboratório de Sistemas Industriais, onde se pretende controlar a passagem de objectos num tapete rolante através de visão por computador. O sistema desenvolvido consiste num tapete rolante accionado por um servo motor da OMRON, com transmissão por correia. O controlo do servo motor é realizado por computador através de uma placa da National Instruments PCI-7344 com o adaptador UMI-7764. O sistema de visão consiste numa placa Matrox Meteor II e uma câmara CCD a cores. Pretende-se controlar a velocidade do tapete em função do numero de objectos a identificar e do tempo de processamento do anel de visão. Para tal foi necessário calibrar o sistema de visão, baseado num PC- Pentium II a 350 MHz com 32 Mb de RAM, tendo o software sido desenvolvido em Visual C++. O sistema de controlo encontra-se centralizado num PC-Pentium III a 850 MHz com 128 Mb de RAM, tendo o software sido desenvolvido no programa LABVIE
The 12 prophets dataset
The "Ajeijadinho 3D" project is an initiative supported by the University of
S\~ao Paulo (Museum of Science and Dean of Culture and Extension), which
involves the 3D digitization of art works of Brazilian sculptor Antonio
Francisco Lisboa, better known as Aleijadinho. The project made use of advanced
acquisition and processing of 3D meshes for preservation and dissemination of
the cultural heritage. The dissemination occurs through a Web portal, so that
the population has the opportunity to meet the art works in detail using 3D
visualization and interaction. The portal address is
http://www.aleijadinho3d.icmc.usp.br. The 3D acquisitions were conducted over a
week at the end of July 2013 in the cities of Ouro Preto, MG, Brazil and
Congonhas do Campo, MG, Brazil. The scanning was done with a special equipment
supplied by company Leica Geosystems, which allowed the work to take place at
distances between 10 and 30 meters, defining a non-invasive procedure,
simplified logistics, and without the need for preparation or isolation of the
sites. In Ouro Preto, we digitized the churches of Francisco of Assis, Our Lady
of Carmo, and Our Lady of Mercy; in Congonhas do Campo we scanned the entire
Sanctuary of Bom Jesus de Matosinhos and his 12 prophets. Once scanned, the art
works went through a long process of preparation, which required careful
handling of meshes done by experts from the University of S\~ao Paulo in
partnership with company Imprimate.Comment: Full dataset online at http://aleijadinho3d.icmc.usp.br/data.htm
Recording from two neurons: second order stimulus reconstruction from spike trains and population coding
We study the reconstruction of visual stimuli from spike trains, recording
simultaneously from the two H1 neurons located in the lobula plate of the fly
Chrysomya megacephala. The fly views two types of stimuli, corresponding to
rotational and translational displacements. If the reconstructed stimulus is to
be represented by a Volterra series and correlations between spikes are to be
taken into account, first order expansions are insufficient and we have to go
to second order, at least. In this case higher order correlation functions have
to be manipulated, whose size may become prohibitively large. We therefore
develop a Gaussian-like representation for fourth order correlation functions,
which works exceedingly well in the case of the fly. The reconstructions using
this Gaussian-like representation are very similar to the reconstructions using
the experimental correlation functions. The overall contribution to rotational
stimulus reconstruction of the second order kernels - measured by a chi-squared
averaged over the whole experiment - is only about 8% of the first order
contribution. Yet if we introduce an instant-dependent chi-square to measure
the contribution of second order kernels at special events, we observe an up to
100% improvement. As may be expected, for translational stimuli the
reconstructions are rather poor. The Gaussian-like representation could be a
valuable aid in population coding with large number of neurons
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